https://www.reddit.com/r/aws/comments/4m2p1y/enhanced_networking_expected_instance_to_instance/
The guide to determining whether it is enabled is here:
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I installed the aws cli and created a new user ‘aws-cli’ to manage the instances
I configured it for oregon (us-west-2)
modinfo needed to be run as root
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Will enhanced networking help? What are the downsides? Why isn’t it enabled by default?
I tried adjusting the MTU (MAXIMUM TRANSFER UNIT) size following this guide:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/network_mtu.html#set_mtu
Initially, the instance had jumbo frames enabled (mtu=9001), which I reduced to 1500, then did not observe any improved throughput.
Finally I span up a linode in California to see if the issue might be latency related.
From CA
I then used iperf to verify the differnce:
west-coast linode -> oregon-ec2 instance: 251 Mbits/sec east-coast linode -> oregon-ec2 instance: 59 Mbits/sec
Dammit, it is. Aparently latency affects bandwidth for TCP. Dammit.
Back to using a CDN… and I need to read the RFC for TCP.
Oh well, at least I now have some concrete numbers for why people use CDNS.
This seems to be the mathematics underpinning the problem I encountered:
https://en.wikipedia.org/wiki/Bandwidth-delay_product